Entomopathogens produce a plethora of substances, called secondary metabolites, to facilitate insect infection and maintain their vital functions. These metabolites not only suppress the insects’ immune system, but can also have direct negative effects on insects such as contact toxicity, antifeedant, egg-laying deterrence, decrease of developmental rate and weight gain and others. Despite decades of intensive research, many aspects of their biosynthesis pathways, modes of action and ecological roles remain poorly understood or even unknown. This chapter describes the current knowledge on the use of secondary metabolites as biopesticides in the context of Integrated Pest Management. The latest studies evaluating their insecticidal activity in laboratory bioassays and field trials are presented. Future challenges and considerations for the full exploitation of secondary metabolites in pest management strategies are discussed.